Thermally responsive control switch for liquid fuel lines



Aug. 8, 1944. B. HAYTER 2,355,436

THERMALLY RESPONSIVE CONTROL SWiTCH FOR LIQUID FUEL LINES FiledMarch 13,1941 2 Sheets-Sheet 1 I n-uenzor .Bruca jfa-zyier B.- HAwr'ER 2,355,436

THERMALLY RESPONSIVE CONTROL SWITCH FOR LIQUID FUEL LINES Aug. 8, 1944.

Filed March 13, 1941 2 Sheets-Sheet 2 hum ' Invefizor .257" 3. 9

mjfazifir Patented Aug. 8, 1944 THERMALLY- RESPONSIVE CONTROL SWITCH FOBLIQUID FUEL LINES .Bruce Hayter, Santa Fe, N. Men, assignor to OilDevices, Santa Fe, N. Men, a

ship of Illinois limitedpartner Application March 13, 1941, Serial No.383,119 1 Claim. (CI-1H8) My invention relates to an improvement incontrol devices forgoil burners and the like, and has for one purposethe provision of means for controlling or varying the fiow of fuel to aliquid fuel burner in response to changes in the temperature conditionsadjacent the burner.

Another purpose is the provision of a control device for use with pottype burners which oper-' ates in response to an undesired increase intemperature at or adjacent the pot.

Another purpose is the provision of means for cutting 011 or reducingfuel fiow to a pot type burner-having a booster fan in response tofailure -of the fan or fan' motor.

Other purposes will appear from time to time in the course of thespecification and claim. I illustrate my invention more or lessdiagrammatically in the accompanying drawings wherein:

Fig. 1 is a vertical section; Fig. 2 is a partial vertical section on anenlarged scale of a variant form of the device;

Fig. 3 is a partial vertical section illustrating a variant form ofswitch; 1 Fig. 4 is a similar section illustrating a still furthervariant form of switch; and

Fig. 5 illustrates a variant form of switch control. Like parts areindicated by like symbols throughout the specification and drawings.

Referring to the drawings, I generally indicates a heater drum, whichmay for example have supporting legs 2. 2 indicates a potlocated withinthe drum and having a plurality of primary air inlet apertures l and atop row of secondary air inlet apertures i. t is any suitable fire ringhavsource of electric power, which may for example be a transformer. 2|is a connection between the thermostatic contact Ito and thetransformer.

2| is a resistance mounted on or in the valve housing generallyindicated as H, and for convenience shown as mounted adjacent awarpingbar 22, both being mounted as upon a bracket 23 on the partition orsupport 24 within the housing cover 2!. The resistance 2! is shown as incircuit with the transformer is as by the conductor 26. 21 and 20indicate conductors extending respec-- tively from the resistance 2| andthe thermostatic fixed contact Ila to any suitable heat responsivemember generally indicated as 29 and located for cmvenience adjacent thepot l. I may find it convenient to locate it on the partition l2 belowbut close to the bottom of the pot 3. I

may employ any thermostatically responsive element but for convenience Iillustrate a snap disc ll associated with the'conductor 2| and the fixedcontact ll associated with the conductor 21.

I It will be understood that the members 30,- may normally be in circuitclosing relation but that, in response to a predetermined increase inthe temperature of or about the switch, the member 2! may snap intocircuit breaking position, which breaks the circuit through theresistance It. The circuit, of course, can be closed only when thethermostatic contacts Ila and llb are in the circuit closing position inwhich they are shown in Fig. 1.

when the heat to which the switch 29 is subjected ing a central apertureI. I indicates a foramiable motor IS, the fan and motor, if desired,beingmounted on a unitary supporting plate I. spaced below the partitionI2 as by any suitable spacers It will be understood that any suitablecircuit may be providedwhereby the motor II may be constantly operatedfrom any suitable source of electric power.-- ll indicatesa thermostat,which may have a normally fixed adjustable contact I its and a movablecontact llb, which may for example be a bimetallic strip. I! is anysuitable does not exceed a predetermined maximum, the circuit throughthe resistance 2| is closed.

ll indicates any suitable valve stem having a limit abutment disc ll,between which and the bracket 42 is compressed a spring 43. The

' bracket 42 may serve as a bearing for the valve stem I, and the springI! normally tends to urge the valve stem upwardiy as far as the limitdisc II and the adjustable limit stop 44 will permit. Hie valve stem 4|may haves valve member proper I, which may have any suitable metering beunderstood, however, that,-unless a circuit is closed through theresistance 2|,

the warping bar 22 remains in the bottom or full line position in it isFig. 1, in which. position it The parts are so arranged that tion.

is effective to hold the valve stem 40 in bottom position against thecompression of the spring 43, and it is only when a circuit is closedthrough the resistance 2| that the resistance causes the warping bar 22to rise to its dotted line or top position of Fig. l.

Any suitable circuit may be used, extending from the motor I5 to thetransformer l9, if constant operation is desired, or the motor circuitmay be controlled by a room thermostat where its intermittent operationis desired.

In the operation of the device, when heat is called for and thethermostatic contacts Ilia and l8-b are as shown in the circuit closingposition of Fig. 1, the circuit is closed through the resistance 2|, theWarping bar 22 is warped up to the dotted line or release position, andthe spring 43 raises the valve stem to full flow position, and a fullflow of fuel is admitted. At that time the motor I5 is in operation. Thefan It is effective to deliver air under pressure to the space about thepot 3. This delivery of air not merely provides the air necessary forcombustion but has a cooling effect on the switch or the spaceimmediately about it.

If for any reason the fan fails, this cooling eifect ceases and theswitch 29 or the space about it increases in temperature sufficiently tocause the member 30 to snap into circuit breaking position. It will stayin circuit breaking position until the temperature of the pot, and thusof the space around the switch 29, becomes reduced because of thereduced flow of fuel which ensues. If before the device has any furtherattention the pot becomes so far cooled as to permit the member 30 againto snap into circuit closing position, the fuel supply will again bereduced as soon as the space around the switch become overheated becauseof the increased supply of fuel. In other words, the fuel supply will beintermittent,-and the total heating effect will be reduced.

I may find it desirable, as shown in Fig. 3, to provide means forpreventing the member 30 from snapping back into circuit closingposition. I may, for example, have any suitable abutment member orplunger 50, which may be guided by any suitable guide 5|, and which iurged by a spring 52 in the direction of the snap switch member 30. Whenthe snap switch member 30 is in the circuit closing position in which itisshown in dotted line in Fig. 3, its edge engages the plunger 50 andresists the effectof the compression of the spring 52. When the member30 snaps or flexes into theraised or circuit breaking position of Fig.3, the spring 52 is then effective to move the plunger 50 beneath theouter edge of the member 30 to prevent it from thereafter snapping backunless and until the operator pulls on the-actuating rod 53 by theexterior control handle 54 to release the member 30 again to its bottomor circuit closing position of Fig. 3. In Fig. 3 the dotted lineposition of the member 50 indicates its release position, and it isshown in full line as holding the member 30 also in full line positionin its raised or circuit breaking posian alternative form may beemployed, as shown for example in Fig. 4. In that form I illustrate asopposed to the fixed contact 3| a warping bar 56, which is normally heldin circuit closing posi- The fixed contact 3| and the Warping bar 56 maybe mounted on any suitable base element 51, which may be applied forexample to the partition I2. 58 indicates a trigger which may be springthrust as by the spring 59 and the abutment 60 into position to snapunder the outer end of the warping bar 56 when the warping bar rises tocircuit breaking position. Any suitable exterior handle Bl, with thecontrol rod 62, is effective to release the trigger 58 when desired andto permit the warping bar 55 to warp back into circuit closing position.

Fig. 2 illustrates a variant form of the device, which I illustrate inconnection with the same switch 29, as shown in Fig. 1, but which itwill be understood may inferentially include the switch of either of theforms of Figs. 3 and 4. Fig. 2 illustrates my control as applicable to amulti-stage burner. The pot 3 with the bafile housing 8 will beunderstood inferentially to be included in Fig. 2.

Referring to Fig. 2, I illustrate the top of the valve stem, as at 10,normally urged into open position as by the spring 'll. Its upwardmovement is initially resisted by the warping bar 12, the setting ofwhich may be controlled by the adjustable stop 13. This stop may be setto give a minimum or pilot flow, or if the switch were employed with thestructure without a pilot, it might be set for a complete shutofi offuel. Associated with the warping bar 12 is a'resistance 14, shown as incircuit with the fixed adjustable contact 15, which in turn is opposedto the movable contact I6 of any suitable thermostat. TI is atransformer or other suitable power source, in circuit with the roomthermostat and with the resistance 14. It will be understood that withthe switch 29 normally in circuit closing position, a: movement of thethermostatic contact 16 into conductiverelation with the fixed contact15 will close a circuit through the resistance 14 and will cause thewarping bar 12 to warp rapidly upwardly to permit the spring H to raisethe valve. The upward movement of the valve 10 is stopped at anintermediate fiow position by a second warping bar.'|8, the downwardposition of which is limited by any suitable adjusting stop 19. Theresistance I2 is in circuit with the switch 29, and with a secincludedinthe circuit for the resistance "M of the warping bar 12, but. it isincluded in the circuit for the resistance 82 of the warping bar 18.Thus .the safety provision or turndown feature is effecfor theresistance I4 through the contacts 15 and 16. This permits the valve Illto;rise ashigh as the still cold warping. bar 18 will. permit'. vUnlessfurther heat is called'for, this is.as,- far as the valve stem can rise.If still further. heat is called for, the thermostat is 'eifectivetojmove the movable contact 8| into'circuit closing-relationship withthe contact 8l'l. This closes a' cir- 4 cuit'through the resistance' 82for 'thesecond wraping bar 18, which circuit, however, can only beclosed if the contacts of the switch 29 or its equivalent are in circuitclosing position. The result then is to flex the-bar 18 high enough topermit the springll to move the valve-, 'stem 10 to a fully-openposition, controlled or limited by the 'adjustable stop 83 or itsequivalent.

-- It will be understood that themotori 5is-operating at least duringthe high stage. If the motor II, which is inferentially present in Fig.2, for any reason stops operating, then the cooling effect, of the fanon the switch 29 ceases, and the switch 29 shortly moves to circuitbreaking position, which breaks the circuit for the resistance 82 andcauses the warping bar 18 to move the valve stem back to theintermediate flow position. It is understood that the parts are soproportioned that at intermediate flow position the device may operateon natural draft and that non-operation of the motor and fan at theintermediate stage is not harmful.

It will be understood, of course, that in place of the particular switch29, shown in Fig. 2, with the fixed contact 3| and the snap disc 30, Imay substitute either of the switch structures shown in Figs. 3 and 4,which in both cases show means for holding the circuit open once it hasbeen broken by the change in heat conditions, until the operator againreleases either the plunger 50 of Fig. 3' or the trigger 5 8 of Fig. 4.

Referring to Fig. 5, I illustrate a switch control, which is shown assubstantially identical with the switch structure of Fig. 4 except thatin the place of the pivoted trigger 58, I illustrate a wanping bar 9|!mounted on any suitable base or bracket 9|, with which is associated atresistance 82, in circuit with the thermostat and the transformer. Itwill thus be seen that a circuit is closed through the resistance 92 atall times that the thermostatic contacts I81; and lab are in circuitclosing position.

It will be understood that, when the resistance 92 is heated, it causesthe warping bar 90 to tend. to flex against the end of the switchelement 58 in such fashion that whenever the switch element or warpingbar 56 warps upwardly to circult breaking position, the end of thewarping bar warps in beneath it and prevents it from again returning tocircuit closing position. -I illustrate an exterior manual knob 93,which, through any suitable tension member 94, may be employed manuallyto withdraw the warping bar 90 to permit the downward movement of thewarping bar 56. This manual operation may be made unnecessary by anopening of the thermostatic contacts which will break the circuitthrough the resistance 92 and permit the warping bar 80 to warp intoinoperative position. 0therwise the control, so far as the valve is con-.cerned, is the same.

grammatic, rather than as limiting me to my precise showing.

I claim: 1 I

In combination, a pot type burner, a fuel line therefor, a valvecontrolling the fuel line, electrically actuated means for controllingthe valve, a circuit including said means and adapted when energized toopen the valve, the burner including a pot, an air chamber and a fan, athermostatically actuated switch in the air chamber exposed to the flowof air fromthe fan, contacts associated with said switch adapted toclose the circuit when the thermostatically actuated switch is in a coldcondition and to open the circuit when the switch is heated saidthermostatically actuated switch being subjected directly to the heat ofthe pot.

BRUCE HAY'I'ER.

